I've never compared the two, but will 4th gen front brake calipers bolt on or not? If not what kind of fab/mods are required, and are they even much of an upgrade at all???

 

No they will not.

Yes the LS1 ones are a significant upgrade.

Read the "sticky" threads at the top of this forum. Visit www.bigbrakeupgrade.com as well for info and a possible source.

 

I have not done the mod yet, but my understanding is that it's a huge improvement over the smallish thirdgen rotors and calipers.

this looks like the most affordable option if you want to keep with factory 16" wheels.
http://www.bigbrakeupgrade.com/ls1_complete.html

 

What about doing the rear discs?

If I keep my little 10" rear discs, they'll look kind of out of place.

 

Those 10" rear brakes look kind of out of place on anything, no matter what... they make your car look just exactly like it has brakes tha tbasically don't work.

In a perfect world, you would swap PBR rears with their near 12" rotors in place of those Saginaw rears. Might be possible to put a whole 4th gen setup on there, except with non-ABS plumbing. Don't know, never tried it myself since I already have a 3rd gen PBR system on my car, but that would be my line of research if I were in that situation I think.